@Johann JellsThe trap on the floor drain is {theoretically} water filled ... the condensate/drainage line from the HRV sees to that.  

Let me condense this as much as I can...

I want something to teach me what to do when the manual states "call a professional HVAC technician" Most of my (condensing) furnace service calls end up being fixed by replacing a pressure switch, thermostat,  or controls board. 

the boot camp condenses months of meandering into a few days...but so does his books.     

I agree with Curt's advice, approx. 500 sq ft per ton...I also just paid $3,500 for coil/condenser 3 ton unit replacement for a 1,600 sq ft house...The biggest issues you will face with a home that old is running the duct work...If you are not planning on opening the walls, another option is two units, one for each floor so the duct work is only in the attic and basement...A little more costly, so you have to balance out the total costs of opening the walls (or not) if it is not necessary...

I have the same one in my own house - originally because it blends well with my solar hot water heating system, although now I also take a loop off through a little plate frame heat exchanger to make 'boiler water' to heat my second floor.I didn't like buying the SS stack pipe so my next tankless will be a condensing Navien.

I'm in the beginning stages, so I'm trying to condense all of the information out there to must have resources/references everyone needs in the beginning stages.

If you are looking for specifics condensed into one source, "The Book on Rental Property Investing" by Brandon Turner from this site is a great one that walks you through from start to rentals and even common problems you would encounter with tenants in your property.  

That person's report says it is totally normal due to condensation.

He is doing the walk through and one of his employees would complete.These units 15 of them have tenants living in them.The complaints are leaky faucets,to pipes on the condenser line leaking,to when they flush the toilet upstairs there is a leak above the kitchen etc.There is only one unit out of the 5 vacant where they went in and took out some copper.I can have my PM watch the whole job and make sure they stay on task.